相关疑难解决方法(0)

import "reflect-metadata"

function validate(target: any) {
  let paramtypes = Reflect.getMetadata("design:paramtypes", target);
  console.log(paramtypes);  // undefined
}

@validate
class Log {
  constructor(public readonly xx: string) {}
}

打我启动服务器，打开网页发现paramtypes未定义

tsconfig.json

{
  "compilerOptions": {
    "target": "ESNext",
    "lib": ["DOM", "DOM.Iterable", "ESNext"],
    "allowJs": false,
    "skipLibCheck": false,
    "esModuleInterop": false,
    "allowSyntheticDefaultImports": true,
    "strict": true,
    "forceConsistentCasingInFileNames": true,
    "module": "ESNext",
    "moduleResolution": "Node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "noEmit": true,
    "jsx": "react",
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true
  },
  "include": ["./src"]
}